3-Phase BLDC Motor Sensorless Control Using MC56F8013

Software DesignBecause this interrupt has the highest frequency, FreeMaster recorder is also put inside. It alsocreates a timebase for button processing.• ADC limit and zero crossing detection — IsrADCLimitThe calling period depends on the motor speed. At 2000 RPM for a 2-pole-pair motor, the zerocrossing period is 2500 µs.The zero crossing detection part detects zero crossings and performs actions related with zerocrossing detection. It cooperates with drivers inside BldcZC.c.• IsrPWMReloadThe calling period is defined by the PWM frequency and the PWM reload prescaler. In thisapplication, the calling period is 50 µs.It reloads the PWM duty cycle, calculated by the speed PI controller. This interrupt is included forfuture expansion.3-Phase BLDC Motor Sensorless Control using MC56F8013, Rev. 054 Freescale Semiconductor